[lkml]   [2001]   [Aug]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
On August 19, 2001 11:11 pm, Otto Wyss wrote:
> I recently wrote some small files to the floppy disk and noticed almost nothing
> happened immediately but after a certain time the floppy actually started
> writing. So this action took more than 30 seconds instead just a few. This
> remembered me of the elevator problem in the kernel. To transfer this example
> into real live: A person who wants to take the elevator has to wait 8 hours
> before the elevator even starts. While probably everyone agrees this is
> ridiculous in real live astonishingly nobody complains about it in case of a disk.

My early flush patch, posted a month or so ago, takes care of this nicely.
I'm just waiting for 2.5 to roll around to do some more work on it.

> [...]
> Could anybody produce any real figures to prove/disprove my theory? Could
> anybody benchmark the disk access for the 3 waiting times (0, 200ms 30sec) with
> different loads?

Your theory is correct. I implemented the idea, took measurements, and found
dramatic performance improvements under some loads, while getting worse on
none. You can search for a nice writeup by Jonathan Corbett.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 12:58    [W:0.062 / U:1.884 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site